Model-based noise suppression techniques for suppressing noise using a speech model which models the features of speech have been developed. A model-based noise suppression method is a method for suppressing noise with high accuracy by referring to speech information of a speech model and is disclosed, for example, in Patent Literature 1, Non-Patent Literature 1, and Non-Patent Literature 2.
For example, Patent Literature 1 discloses a noise suppression system which uses a speech model. The noise suppression system disclosed in Patent Literature 1 obtains temporarily estimated speech in a spectrum region from an input signal and an average spectrum of noise and corrects the temporarily estimated speech using a standard pattern. The noise suppression system calculates a noise reduction filter from the corrected temporarily estimated speech and the average noise spectrum and calculates estimated speech from the noise reduction filter and an input signal spectrum.